Texas

I've lived in MA, MN and MD. The further south, the more likely any snow is to be accompanied by ice.

Personal opinions:
1) up to six inches of snow is easier to drive on than any accumulation of ice.
2) Availability of countermeasures is far superior in northern climates. Plows for snow removal (and bless the public plow-drivers as well as all the northern redneck in-laws that have a plow on the front of their 4WD pickup truck to clear out apartment building and business parking lots.) Ice melt. Sand/other road treatments for when the temperature's too low for salt to melt the ice.